ABSTRACT

To measure the contact angles of smaller particles, or clusters, more accurately, high-resolution electron micrographs (HREM) were taken. Figure 2(a) and (b) shows an example . Before melting (a), the cluster shows lattice fringes, the orientations of which are different from one place to another, indicating that this particular cluster was polycrystalline at least when imaged. After melting (b), the cluster became perfectly spherical and the lattice fringes disappeared. Furthermore, the projected area of the Bi liquid cluster is smaller than that of solid one. This is quite reasonable because the volume of Bi shrinks on melting (Faber 1972). The substrate is amorphous, indicating that the substrate is SiO and not Si.